'The arch is isolated on an island which serves no real purpose. It's a fine monument and ought to be in a place where it can be seen and admired.'

The proposal is being considered by a working group which includes TfL, Westminster council, the Royal Parks and Grosvenor and Portman estates. Mr Hendy said moving it would enable tourists to find Speakers' Corner more easily.

'It would be an interesting conjunction between an arch built for royalty and a place of public oratory open to everyone,' he told The Times.

John Nash's 1827 creation, modelled on the Arch of Constantine in ancient Rome, was intended as a ceremonial entrance to Buckingham Palace.

However, it was found to be too narrow for the sovereign's gold state coach and was moved to its present site in 1851, where it became the north- eastern entrance to Hyde Park. But the arch found itself marooned on what has become one of London's busiest roundabouts in 1960 after a section of the park was concreted over to make way for the northbound carriageway of Park Lane.

Today almost 6,000 vehicles an hour drive around the arch at peak times. It has remained stranded on the island for so long partly because the land around it falls under so many jurisdictions.

TfL is considering a number of options with the working group. Several attempts have been made over the years to free the 45ft-high monument, built as a memorial to the Napoleonic Wars, from its position. In 1996, a £21 million scheme to pedestrianise the area between the arch and Speakers' Corner was shelved after warnings that it would worsen congestion.

Six months later, a £75million traffic-improvement plan was dropped when architects decided the arch looked best where it was.

Rowan Moore, director of the Architecture Foundation and the Standard's architecture critic, said: 'If it makes that kind of hideous corner of London work better for the public, then why not? There is nothing sacred about the position of the structure-You stop noticing it after a while. If you moved it, people might start noticing it again.'

Theo Moore, spokesman for the Royal Parks Agency, which runs Hyde Park, said moving the 'national treasure' of Marble Arch was being looked at closely.

He said: 'Marble Arch would make a pretty great entrance to the park's north-east corner.

'Members of the public, when they're walking down Oxford Street, might imagine a very grand entrance into what is a very special park. It would make a great junction and joining point between two famous landmarks.'